Depth to Magnetic Sources Using Spectral Analysis of High Resolution Aeromagnetic Data Over Machina and Environs, Northeastern Nigeria
Bibliographic record
Abstract
Analysis of high resolution aeromagnetic data over Machina and its environment shows areas of low total magnetic intensity contour values are hosts to thicker overburden sediments and near surface intrusive rock bodies reside over high total magnetic intensity contour regions. Positive and negative residual anomaly values depict the presence of basic and acid rock units; however, the acid rocks dominate over the basic components. Major linear features of the residual anomaly are oriented along the NE – SW direction. Some linear features however, cross cut the major lineaments along the NW – SE, N –S, and E – W directions. A NW – SE cross section of the residual anomaly shows irregularity of the bedrock floor. The negative residual anomalies are underlain by granite rocks, while the positive values are within the domain of basic intrusive. Determination of the magnetic source depth revealed depths to the top of the deeper and the shallower sources ranging from 0.6 – 2.0 km and from 0.4 - 0.9 km respectively. Thicker sedimentary covers are underlain by basement rocks while; shallower magnetic horizons are composed of intrusive igneous bodies. Maximum sedimentary thickness of 2.0 km in the study area might not be adequate enough for hydrocarbon maturation and accumulation. Segment directional histogram data shown on rose diagram exhibits strike directions along the E – W, NE – SW, NW – SE, NNE – SSW and NNE – SSW. Most of the fracture lines dip at angles lower than 10 degrees. The north dipping direction group of lineaments is prevalent. Orientations of the structural elements are in conformity with the dominant regional structural grain of the country. Cross- cutting of the lineaments may be related to the geothermal energy in the area as higher interconnected lineaments are associated with higher geothermal energy. Rugged terrain reliefs might have resulted from the effects of tectonic and structural evolution in the area. Variability of the dip angles is associated with non-uniform framework of the forces of deformation on the rocks and/or differential responses of the rocks to the stress imposed on them.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".